1 Volume MMV. No. 10

October 2005

President: Mark Folkerts (425) 486-9733 folkerts at seanet.com The Stargazer VP & Librarian: Mike Locke (425) 259-5995 mlocke at lionmts.com P.O. Box 12746 Treasurer: Carol Gore (360) 856-5135 janeway7C at aol.com Everett, WA 98206 Newsletter co-editor: Bill O’Neil (774) 253-0747 wonastrn at seanet.com Web assistance: Cody Gibson (425) 348-1608 sircody01 at comcast.net See EAS website at: (change ‘at’ to @ to send email) http://members.tripod.com/everett_astronomy

$$ - FINANCIAL HEALTH - $$ EAS BUSINESS… The club maintains a $500+ balance. We try to keep approximately a $500 balance to allow for contingencies. . NEXT EAS MEETING - SATURDAY OCTOBER 29TH AT CLUB SCOPES 3:00 PM AT THE EVERETT PUBLIC LIBRARY, IN THE AUDITORIUM (DOWNSTAIRS) SCOPE LOAN STATUS WAITING 10-INCH DOBSONIAN ON LOAN NO WAIT LIST October 29th - EAS Meeting – Saturday 3:00 PM - Dr. Paula EAS members: contact Mike Locke at (425) 259-5995 or Szkody from UW Astronomy will discuss recent findings ’mlocke at lionmts.com’ to borrow a scope. about “Cataclysmic Variables: Insights from HST, FUSE, Chandra and SDSS” Don’t miss it ! ASTRO CALENDAR FOR 2005

November 19th - EAS Meeting – Saturday 3:00 PM October 2005 Curtis Snow – Mars Society ‘Changes in perspective / Oct 03 - New Moon "discoveries" from our recent exploration of Mars’ Oct 03 - Annular Solar Eclipse, Visible From Africa

th Oct 04 - Moon occults Mercury December 10 – 7:00 PM - Holiday Dinner – with dinner Oct 05 - Mercury passes 1.3 degrees From Jupiter speaker Keith Allred with CCD imaging presentation Oct 09 - Draconids meteor shower Peak Oct 16 - Venus occults PPM 265560 (7.7 Magnitude ) January meeting - Oliver Fraser of UW Astronomy – Studying Oct 17 - Partial Lunar eclipse the changing period of a Pulsating Star” Oct 21 - Orionid meteor shower peak Oct 29 - EAS MEETING - Saturday 3:00 PM at Everett Public Library

Oct 30 - Daylight Saving - set clock back 1 Hour Map to library - http://www.epls.org/about/mlmap.htm 2702 Hoyt Avenue November 2005 Everett, WA 98201 Nov 01 - New Moon Directions to library - http://www.epls.org/about/mldirect.htm Nov 05 - Potential Saturday EAS star party night, location TBD Nov 03 - Taurids meteor shower peak Nov 03 - Mercury at its Greatest Eastern Elongation (23 Degrees) CLUB STAR PARTY INFO Nov 03 - Venus at its Greatest Eastern Elongation (47 Degrees) Nov 07 - Mars at opposition Upcoming star party schedule - Winding down for the winter. Nov 19 - EAS MEETING - Saturday 4:00 PM at Everett Public Library

People should send mail to the mail list to coordinate spur- of-the-moment Mars observing get-togethers, on nights December 2005 when the sky clears. Dec 02 - 10th anniversary (1995), SOHO Launch Dec 12 - Moon occults Mars We try to hold informal close-in star parties each month during the Dec 12 - Mercury at its Greatest Western Elongation (21 Degrees) spring, summer, and fall months on a weekend near the New Dec 13 - Geminids meteor shower peak moon at a member’s property or a local park. Dec 21 - Winter Solstice, 18:35 UT (call Mike Locke at (425) 259-5995 for info or check the EAS Dec 22 - Ursids meteor shower peak Dec 10th or 17th – EAS Dinner - Saturday 7:00 PM website.) Members contact Mike Locke for scope borrowing.

2 UW Astronomy Colloquium Schedule Dec 01 New Moon Dec 08 First Quarter Moon The Astronomy Department weekly colloquium meets Thursdays at 4:00 pm in PAB A102 (the classroom part of the Digital Lunar Orbiter Photographic Atlas of the Moon Physics/Astronomy Building complex). The Lunar and Planetary Institute has created a digital version of

the Lunar Orbiter Photographic Atlas of the Moon, and OVER THE AIRWAVES Consolidated Lunar Atlas available online at: “Our group of radio script writers now consists of EAS and SAS members Jim http://www.lpi.usra.edu/research/cla/menu.html Ehrmin, Greg Donohue, and Ted Vosk, who are now regularly writing and http://www.lpi.usra.edu/research/lunar_orbiter helping to produce our astronomy radio show, "It's Over Your Head" on radio station KSER, FM 90.7. The six-minute segment is broadcast every Wednesday UP IN THE SKY -- THE PLANETS morning at approximately 7:20 A.M. and gives a weekly look at what's up in the sky over Snohomish County, with other information. If you are a listener to the program, show your support by giving the program director of KSER a call!” Object Rises Transits Sets Con Mag Web page with lots of archives and other info is available at Sun 7:44 am 13:02 18:01 Vir -27 http://www.itsoveryourhead.org/ Mercury Daylight Daylight 18:41 Vir -1.5 KPLU 88.5 FM National Public Radio has daily broadcasts of "Star Date" Venus Daylight Daylight 19:57 Oph -4.3 by the McDonald Observatory of the University of Texas at Austin, Mars 18:35 1:58 am Daylight Ari -2.2 Monday through Friday at about 6:05 pm. The short 2 minute radio show Jupiter Daylight Daylight Daylight Vir -1.7 deals with current topics of interest in astronomy. The University of Saturn 0:15 am 7:41 am Daylight Can +0.3 Washington TV broadcasts programs from NASA at 12:00 AM Monday through Friday, 12:30 AM Saturday, and 1:30 AM Sunday on the Channel Uranus Daylight 21:22 2:46 am Aqr +5.8 27 cable station. Neptune Daylight 19:56 am 0:47 am Cap +7.8 Daylight Daylight 21:08 Ser +13.8 EAS LIBRARY – BOOK & VIDEO LIST (times local time for Everett PDT) The EAS has a library of books, videotapes, and software for members to Transit times for Jupiter’s Great Red Spot in 2005 borrow. We always value any items you would like to donate to this http://skyandtelescope.com/observing/objects/planets/article_107_2.asp library. You can contact a club officer or Librarian Mike Locke, phone (425) 259-5995, email mlocke at lioninc.com, to borrow or donate any NOAA SUN CALCULATOR materials. See list here: Need to know exactly what time the sun will set on Sept. 26, http://members.tripod.com/everett_astronomy/eas_library.htm 2065? Or when it rose in 565 BC? How about the length of daylight a week from Tuesday in Albuquerque, N.M.? Just go to MEMBERSHIP BENEFITS & INFORMATION NOAA's solar calculator, now available on the Web. Membership in the Everett Astronomical Society (EAS) will give you access to http://www.srrb.noaa.gov/highlights/sunrise/gen.html all the material in the lending library. The library, which is maintained by Mike Locke, consists of several VCR tapes, many books, magazines, and software INTERNATIONAL SPACE STATION – VISIBLE SEATTLE PASSES titles. Membership includes invitations to all of the club meetings and star ISS Visibility – parties, plus the monthly newsletter, The Stargazer. In addition you will be able http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/SightingData/Seattle.ht subscribe to Sky and Telescope for $7 off the normal subscription rate, contact the treasurer for more information. Link to registration form: ml or also see link http://www.heavens- http://members.tripod.com/everett_astronomy/application.htm above.com/PassSummary.asp?lat=47.979&lng=- 122.201&alt=0&loc=Everett&TZ=PST&satid=25544 (When renewing your subscription to Sky & Telescope you should send your S&T renewal form along with a check made out to Everett Astronomical MEMBER NEWS Society to the EAS address. The EAS treasurer will renew your Sky and Telescope subscription for you. Astronomy magazine offers a similar Seattle Astro Society Trying To Get a Dark Sky Site opportunity to club members.) ”We feel that we need to raise $25,000 in order to buy something appropriate on the other side of the mountains. We are making EAS is a member of the Astronomical League and you will receive the good progress within SAS. The deal basically is $250 for dark Astronomical League's newsletter, The Reflector. Being a member also allows you the use of the club's telescopes, an award winning 10 inch Dobsonian mount sky membership, and some relatively nominal sum for annual dark sky dues. One would have to be a SAS member to do this, reflector. Contact Mike Locke (425) 259-5995 to borrow a telescope. EAS dues are $25. but that is a rather nominal charge. We were wondering if Send your annual dues to the Everett Astronomical Society, P.O. Box 12746, anyone in your club would be interested in taking part. I Everett, WA 98206. Funds obtained from membership dues allows the Society to personally think that the dark sky site is a necessary thing for SAS publish the newsletter, pay Astronomical League dues and maintain our library. to do; otherwise, the club really has little tangible to offer its members. With a dark sky site, even city-bound members would OBSERVER’S INFORMATION… have a place within a few hours where they could view from a dark site; even us suburban folks would benefit, I think. Thanks for your consideration.” LUNAR FACTS -- Mark de Regt, SAS.

Oct 17 Full Moon OF THE MONTH: AND Oct 25 Last Quarter Moon Nov 02 New Moon FORNAX, RETICULUM: As the October-November skies begin to Nov 09 First Quarter Moon more steadily cloud up, it would be interesting perhaps to broaden Nov 16 Full Moon our “ horizons” by learning a little bit about two Nov 23 Last Quarter Moon constellations (which both have late Fall midnight culmination 3 dates) that are not completely visible, or visible at all, from our Reticulum (the Net (no, not that ‘net’!!)) borders on the latitude. constellations of Dorado, Horologium, and Hydrus. It is 24th in overall brightness, and ranks 82nd in size, and has 11 with a Fornax: “The Laboratory Furnace” as this constellation is also magnitude greater than 5.5. Its central point is at RA=3h54m, known, borders on the constellations of Cetus, Eridanus, Phoenix, th and its Dec. = -60 degrees, and is completely visible from and Sculptor. It ranks 87 (next to last, or the second dimmest) in latitudes S of +23, and completely invisible from latitudes N of +37 overall brightness among the constellations, containing 12 stars degrees. It has no associated Messier objects, and no associated brighter than magnitude 5.5. Its central point is located at meteor showers. Its midnight culmination date is November 19th. RA=2h46m and Dec.= -32 degrees. It is completely visible from The star Zeta Reticuli was the subject of one of the most famous latitudes South of + 50 degrees, and completely invisible from st and much publicized “UFO incidents”, when, in 1961, Betty and latitudes North of +64 degrees. This constellation ranks 41 in Barney Hill from New Hampshire claimed they were abducted by overall size, taking up 397.50 square degrees, or 0.964% of the aliens who showed Mrs. Hill a star map. The area described by sky. Fornax has no known meteor showers and no Messier the map, upon further study, described an area near the double objects; it also has no associated asterisms. Its midnight star system of Zeta Reticuli. All three of these constellations are culmination date is November 2nd, and its solar conjunction date is th among the 14 constellations that Lacaille devised while at the May 4 . Fornax is one of 14 constellations invented by Lacaille Cape of Good Hope in 1751-2. Reticulum also contains many while at the Cape of Good Hope in 1751-2. lesser known double, multiple, and variable stars, as well as Most of the celestial objects found in Fornax are , and galaxies such as NGC-1313 (an S-B nuclear barred ) and th most of them are faint. However, if they can be viewed from NGC-1543 (an E-0/S-0 12 magnitude galaxy). one’s latitude and with adequate amateur telescopic equipment, many of them are beautiful. One of the most beautiful is NGC- YOUNG ASTRONOMER’S CORNER 1097, a 9.3’ x 6.6’ barred spiral with a magnitude of 9.3. Being fairly bright and nearly face-on, NGC-1097 is one of the best FUN FACT: IT TAKES THE SUN’S LIGHT (I.E., HEAT AND ENERGY) barred spirals in the sky. With an eyepiece that gives a APPROXIMATELY EIGHT (8) MINUTES TO REACH THE . magnification of approximately 12x per aperture inch, a small The SUN: The Sun is not just a uniform “ball of fire”. It is a very telescope should show a bright and round nucleus which is interesting and variable structure. The nearest star to earth is encircled by an oval-shaped, somewhat fainter nebulosity. The the center of gravity of our solar system, and keeps the other “bar”, which should be visible in 6-inch scopes with good seeing, planets in their orbits. It is a star that is very much still evolving, is a relatively brighter strip of nebulosity running through this and is classified as a middle-aged star. Its light spectrum also fainter oval halo. Larger scopes may show faint, semi-circular classifies it as a relatively cooler yellow star (compared to hotter, extensions on each of the bar’s ends, and these extensions and younger, blue or white stars), and although it contains mostly denote light from the galaxy’s spiral arms. Slightly northwest of th hydrogen and helium, it also contains ionized calcium and other the northern spiral arm of NGC-1097 lies NGC-1097A, a 13 - metal lines in its spectrum (the chemical and physical analysis of magnitude . A very interesting its light). The sun generates its heat and light (i.e., its energy), by (magnitude = 13, with a 24” diameter) is known as NGC-1049, nuclear fusion of hydrogen in its core, and it is losing its mass (its and is actually a huge globular cluster positioned about 170 substance) in the form of heat, light, and electromagnetic kiloparsecs away in the galaxy, one of the Local radiation, at the rate of 4,000,000 tons per second. Outside of the Group galaxies. The Fornax dwarf galaxy itself was discovered in core, the sun has two other important zones that help to transport 1938, and is one of several, very small elliptical galaxies scattered energy to its surface: the inner radiative zone, and the outer throughout the . The Fornax dwarf galaxy is one of convective zone. The surface of the sun that we see ( the the smallest galaxies known (only 2 kiloparsecs across), and photosphere) is the boundary between its inner layers and the contains only about 50 times as much mass as a representative transparent outer layers (corona); almost all of the energy given globular cluster. Interestingly enough, NGC-1049 is off by the sun into space is given off by the granular-appearing easier to view by amateur scopes than is the Fornax dwarf galaxy (mottled-looking) photosphere. The sun also rotates, faster at its itself. Fornax also contains a bona-fide , called equator, just like the earth. Above the photosphere is the (cleverly enough!!) the Fornax Galaxy Cluster; this group contains (where the temperature begins to rise greatly), and eighteen bright and at least 10 faint galaxies, all of which are this region extends into the corona (the very high temperature, compacted into about a six-degree diameter circle. Most of the gas-like streamers that are visible during an eclipse around the cluster members lie between 20 and 25 megaparsecs away. disc of the sun), which extends millions of miles out from the sun These cluster galaxies include NGC-1380 ( of into the interplanetary medium, where the solar wind carries heat, magnitude 11.1, which itself is surrounded by many other fainter light, and elementary particles (some of which cause the cluster members in a single one-degree field); NGC-1365 “Northern Lights” (see below) when they hit the earth’s (magnitude 9.5, large face-on barred spiral); NGC-1427 (12.2 atmosphere) to the farthest reaches of the solar system. The sun magnitude elliptical); and NGC-1316 (bright peculiar barred spiral, has a magnetic field, and sunspots (intense, localized and cooler and a very dusty galaxy with a bright nucleus that is also a strong portions of the magnetic fields) within the photosphere. The age radio source: it is designated radio source Fornax-A). Also within of the sun is 4.6 billion , and after the same amount of time, the confines of the constellation Fornax are NGC-1406 it will become a “red giant”, and then a “white dwarf” before it dies. (magnitude 12.6 spiral), NGC-1255 (11.1 magnitude spiral), NGC- The sun is not just a “ball of fire”; it is much more interesting than 1371 (11.5 magnitude barred spiral), NGC-1385 (magnitude 11.2 that! spiral), and NGC-1398 (a fairly bright barred spiral). Fornax also contains one of the southern sky’s best planetary nebulae, NGC- The “Northern Lights” or aurora borealis (there are also “Southern 1360. NGC-1360 has a very high surface brightness, with an Lights” or aurora australis) is a display of diffuse, changing estimated magnitude of 8.0 and a central star of approximately colored light (usually varying hues of blue, green, or red, but it can 12th magnitude, and measures 6.5 arc-minutes across. also be whitish and yellowish in color) seen very high (about 60 miles up) in the Earth’s atmosphere, usually in the regions of the poles. They can appear in spectacular formations, such as 4 streamers or curtains. These lights form around two irregular, Southern Hemisphere (to the ones we are already familiar with in changing ovals which are centered on the Earth’s magnetic poles; the Northern Hemisphere). The general class of object will first be these ovals get bigger (and dip more south, as they did recently) defined, and then a representative object from each hemisphere during periods of high solar activity. Aurora are caused by will be described. Note: “MIRROR” IMAGES” is strictly the name charged particles from the solar wind (the flow of energetic of the new column, and is not intended to imply that there is charged particles (like protons and electrons) from the solar optical mirror symmetry between the two objects. corona) and solar flares (explosive releases of particle and radiation from the upper solar chromosphere and inner corona) CLASS OF OBJECT: LUMINOUS BLUE VARIABLES (LBVs): which carries energy that becomes trapped in the Earth’s A class of very massive luminous blue stars well-known for magnetic sphere; beams of charged particles are then focused sporadic mass ejections; sub-classes of these objects include P- into the upper atmosphere. These beams are then sent spiraling Cygni Stars and Hubble-Sandage variables. These stars are along Earth’s magnetic field lines toward the two poles. Here generally found near the upper limit in the observed H- these charged particles interact with atoms and molecules in the R diagram; most are thought to have evolved from stars with Earth’s atmosphere to produce the beautiful displays that we initial masses greater than 40 solar masses. The mass ejections frequently see on Earth, especially and usually (but not always) at detected in these objects are thought to be due to instabilities in higher latitudes. their stellar envelopes induced by radiation pressure. LBV’s show different types of variations with a wide range of time scales. The largest are correlated with sudden brightenings by more than 3 ASTRONOMY AND TELESCOPE LINGO magnitudes lasting for several hundred to several thousand years. The smallest, which are less than 0.5 magnitude, last several ASTRONOMY LINGO: IMMERSION: The entry of a celestial months to several years. body into a state of invisibility during an eclipse or occultation. REPRESENTATIVE NORTHERN HEMISPHERE OBJECT: TELESCOPE LINGO: SMTO: Abbreviation for: Submillimeter P-Cygni: A massive LBV lying about 2,000 away in the Telescope Observatory. This observatory is a joint facility of the constellation of Cygnus. It has undergone random outbursts in University of Arizona’s Steward Observatory and the Max-Planck the past (in 1600 and 1653 it considerably brightened then faded); Institute for Radioastronomy in Bonn, Germany. The SMTO is since 1700 its brightness has gradually increased. P-Cygni is located on Arizona’s Mount Graham at an altitude of 3186 feet; it also an ultraviolet source: it is however gradually cooling, and the houses the Heinrich-Hertz Submillimeter Telescope, a 10-meter U-V brightness is diminishing as the visual brightness is dish with a surface accuracy of 12 micrometers. increasing.

PLANETARY FOCUS REPRESENTATIVE SOUTHERN HEMISPHERE OBJECT: Eta Carinae: Among the most luminous and unstable stars in the Planetary Focus will return next month. entire Milky Way Galaxy, this LBV lies at a distance of 2,000 parsecs in the southern constellation of Carina. It undergoes ASTRONOMY FUN FACTS large variations in magnitude at very irregular periods. From 1835-45 it was brighter than every star except Sirius, reaching a  The variable star Eta Carinae was bright for over 100 years magnitude as bright as –0.8; since 1880, the magnitude range before it flashed its record brilliance in 1843. The 1843 Eta has been between 5.9 to 7.9. Eta Carinae is surrounded by a Carinae star flash has been estimated at several million times shell of cool dust that is thought to have contributed to its more luminous than the Sun, making Eta Carinae the most decreased light output after about 1843 since that dust was brilliant and luminous star ever recorded. At this luminosity, it ejected; the dust obscures the light output of the star, (which may could have been observed with a powerful telescope (such as the very well have remained constant), and the dust converts the light 200-inch Mount Palomar reflector) from over 450 million light to infrared energy. The total luminosity of this star is about years away!!! 5,000,000 (yes, 5 million!!) times that of the Sun, and its mass is  Vesta, the 4th asteroid to be discovered (in 1807), is the about 120 times that of the Sun. A small of ejected gas brightest of all the asteroids. This is true probably for two that surrounds it contains a very high proportion of nitrogen, reasons: it is relatively large (about 450 kilometers across), and it indicating that substantial nucleosynthesis has taken place. is highly reflective (it is probably composed of basaltic minerals). Sometimes, Vesta can be seen with the naked eye as a faint ASTRONOMICAL NOTES -- ON & OFF THE NET... speck of light. The darkest or blackest asteroid known is 324 Bamberga, which is nearly as dark as the soot from your MARS LOOMS BIG AND BRIGHT AS IT SWINGS CLOSE TO fireplace!! EARTH  Van Biesbroeck’s star, a cool M-class star about 20 light- Look east late these evenings and you'll see a big, fiery yellow years away, is a red dwarf. It is almost 600,000 times dimmer "star" shining much brighter than any other. This is the planet than the Sun. If it were in the same physical position as the Sun, Mars, and it's passing unusually close to Earth during late it would shine only a bit brighter than a full Moon. At its actual October and early November 2005. Anyone can see it -- no location, this star is invisible to the naked eye: to see van matter how little you know about the stars or how badly light- Biesbroeck’s star from Earth would be like seeing a 60-watt light polluted your sky may be. During mid- to late October, look for bulb at a distance of 34,000 miles!!!! Mars glaring low in the east after 8 p.m. local daylight-saving time. In November, it's there in view as early as 6 p.m. standard time. MIRROR IMAGES Later in the evening, Mars climbs higher into better view and shifts over to the southeast. There's nothing else nearly as bright “MIRROR” IMAGES”: Because we live in the Northern that you can confuse it with. Mars will be closest to Earth on the Hemisphere, we often tend to focus (in both observing and night of October 29-30, passing 43.1 million miles (69.4 million reading) on celestial objects in this hemisphere. The point of this kilometers) from our planet around 11:25 p.m. on the 29th column is to inform club members about similar objects in the 5 Eastern Daylight Time. However, Mars will look just about as big accuracy, and spatial resolution, we achieve," said Dr. Jack and brilliant for a couple of weeks before and after that date. Mars Connerney, co-investigator for the Mars Global Surveyor is at opposition (opposite the Sun in our sky) on November 7th. magnetic filed investigation. This means it rises at sunset, is up all night, and sets at sunrise. This is the nearest that Mars has come since its record-breaking "This map lends support to and expands on the 1999 results," close approach in August 2003. At that time it passed by at a said Dr. Norman Ness. "Where the earlier data showed a distance of only 34.7 million miles (55.8 million kilometers), the "striping" of the magnetic field in one region, the new map finds closest it had come in nearly 60,000 years. But for amateur striping elsewhere. More importantly, the new map shows evidence of features, transform faults, that are a "tell-tale" of plate telescope users, now is still a very special time. The planet will tectonics on Earth." Each stripe represents a magnetic field reach an apparent diameter of 20.2 arcseconds (the angular size pointed in one direction_ -- positive or negative_ -- and the of a penny seen at a distance of 620 feet), offering an usually alternating stripes indicate a "flipping" of the direction of the detailed view of its surface. That compares with 25.1 arcseconds magnetic field from one stripe to another. Scientists see similar in August 2003 (the angular size of a penny at 500 feet), and only stripes in the crustal magnetic field on Earth. Stripes form 15.9 arcseconds at Mars's next swing-by, in December 2007 (a whenever two plates are being pushed apart by molten rock penny at 800 feet). In fact, not until the summer of 2018 will coming up from the mantle, such as along the Mid-Atlantic Ridge. Mars again come as close to Earth as it is right now (this As the plate spreads and cools, it becomes magnetized in the statement remains true until mid-November). Moreover, this direction of the Earth's strong global field. Since Earth's global skywatchers at the latitudes of North America and Europe have a field changes direction a few times every million years, on big advantage they didn't have in 2003. That year Mars was far average, a flow that cools in one period will be magnetized in a south in the sky and never got very high for telescope users at different direction than a later flow. As the new crust is pushed out mid-northern latitudes. But this time Mars is farther north and and away from the ridge, stripes of alternating magnetic fields rises higher during the night, affording a sharper, cleaner view in aligned with the ridge axis develop. Transform faults, identified by a telescope through Earth's blurry atmosphere. "shifts" in the magnetic pattern, occur only in association with Telescope Tips - Good as this fall's showing is, surface details on spreading centers. To see this characteristic magnetic imprint on Mars are always a pretty tough target in a telescope. To begin Mars indicates that it, too, had regions where new crust came up with, Mars is only about half the size of Earth. Even at its closest, from the mantle and spread out across the surface. And when you under high magnification it will appear as only a surprisingly small, have new crust coming up, you need old crust plunging back bright ball with some subtle dark markings, possible white clouds down_ -- the exact mechanism for plate tectonics. Connerney around its edges, and perhaps a tiny remnant of the white South points out that plate tectonics provides a unifying framework to Polar Cap shrunken in the warmth of the Martian summer. The explain several Martian features. First, there is the magnetic brightest yellow areas are deserts covered by fine, windblown pattern itself. Second, the Tharsis volcanoes lie along a straight dust. The darker markings are terrain displaying more areas of line. These formations could have formed from the motion of a bare rock or darker sand and dust. Mars rotates every 24 1/2 crustal plate over a fixed "hotspot" in the mantle below, just as the hours, so you can see it turning in just an hour or two of watching. Hawaiian islands on Earth are thought to have formed. Third, the To see much detail on Mars, several things all have to be working Valles Marineris, a large canyon six times as long as the Grand in your favor. You'll need at least a moderately large telescope Canyon and eight times as deep, looks just like a rift formed on with high-quality optics. And you'll need to wait until Mars rises Earth by a plate being pulled apart. Even more, it is oriented just high in the sky, well above the thick, murky layers of Earth's as one would expect from plate motions implied by the magnetic atmosphere near the horizon. Moreover, the atmospheric "seeing" map. "It's certainly not an exhaustive geologic analysis," said must be good. This is the astronomer's term for the constant Dr. Mario Acuña, principal investigator for the Mars Global fuzzing and shimmering of highly magnified telescopic images Surveyor magnetic filed investigation at Goddard Space Flight due to the tiny heat waves that are always rippling through the Center. "But plate tectonics does give us a consistent explanation atmosphere. The seeing changes from night to night and of some of the most prominent features on Mars." sometimes from moment to moment. http://www.nasa.gov/centers/goddard/news/topstory/2005/mgs_pl http://skyandtelescope.com/aboutsky/pressreleases/article_1613_1.asp ates.html Mars: Which Side Is Visible? http://skyandtelescope.com/observing/objects/planets/article_997_1.asp MARS' CLIMATE IN FLUX: MID-LATITUDE GLACIERS

NEW MAP PROVIDES MORE EVIDENCE MARS ONCE LIKE New high-resolution images of mid-latitude Mars are revealing glacier-formed landscapes far from the Martian poles, says a EARTH leading Mars researcher. Conspicuous trains of debris in valleys, NASA scientists have discovered additional evidence that Mars arcs of debris on steep slopes and other features far from the once underwent plate tectonics, slow movement of the planet's polar ice caps bear striking similarities to glacial landscapes of crust, like the present-day Earth. A new map of Mars' magnetic Earth, says Brown University's James Head III. When combined field made by the Mars Global Surveyor spacecraft reveals a with the latest climate models and orbital calculation for Mars, the world whose history was shaped by great crustal plates being geological features make a compelling case for Mars having pulled apart or smashed together. Scientists first found evidence ongoing climate shifts that allow ice to leave the poles and of plate tectonics on Mars in 1999. Those initial observations, also accumulate at lower latitudes. "The exciting thing is a real done with the Mars Global Surveyor's magnetometer, covered convergence of these things," said Head. "For decades people only one region in the Southern Hemisphere. The data was taken have been saying that deposits at mid and equatorial latitudes while the spacecraft performed an aerobraking maneuver, and so look like they are ice-created," said Head. But without better came from differing heights above the crust. This high resolution images, elevation data and some way of explaining it, ice outside magnetic field map, the first of its kind, covers the entire surface of Mars' polar regions was a hard sell. Now high-resolution of Mars. The new map is based on four years of data taken in a images from the Mars Odyssey spacecraft's Thermal Emission constant orbit. Each region on the surface has been sampled Imaging System combined with images from the Mars Global many times. "The more measurements we obtain, the more Surveyor spacecraft's Mars Orbiter Camera and Mars Orbiter 6 Laser Altimeter can be compared directly with glacier features in Star Adaptive Optics system (LGS AO). Since 2003, this system mountain and polar regions of Earth. The likenesses are hard to has been providing very high spatial resolution imaging in the ignore. For instance, consider what Head calls "lineated valley infrared comparable to that of visible light images from Hubble fill". These are lines of debris on valley floors that run downhill and Space Telescope. With LGS AO, observers not only get higher parallel to the valley walls, as if they mark some sort of past flow. resolution, but the light from distant objects is concentrated over a The same sorts of lines of debris are seen in aerial images of much smaller area on the instrument detector, making faint Earth glaciers. The difference is that on Mars the water ice detections possible. The results are quickly advancing the sublimes away (goes directly from solid ice to gas, without any understanding of binary objects, a region in the Solar liquid phase between) and leaves the debris lines intact. On Earth System beyond the orbit of Neptune. the lines of debris are usually washed away as a glacier melts. The lines of debris on Mars continue down valleys and converges The Keck LGS AO system has also been used to look at other with other lines of debris -- again, just like what's seen on Earth recently discovered large bodies in the Kuiper belt. A small moon where glaciers converge. "There's so much topography and the was found circling around 2003 EL61 (codenamed "Santa") but debris is so thick (on Mars) that it's possible some of the ice might none was found orbiting 2005 FY9 ("Easterbunny"), the two still be there," said Head. The evidence for present day ice largest known Kuiper belt objects after Xena and Pluto. "When we includes unusually degraded recent impact craters in these areas test collision models to predict how Pluto and Charon formed, the -- just what you'd expect to see if a lot of the material ejected from models kept producing tiny satellites, much smaller than Charon," the impact was ice that quickly sublimed away. added Brown "But we had never seen satellites that small before in the Kuiper belt. But then we found a moon in the Santa system, Another peculiarly glacier-like feature seen in Martian mid- and then we found another moon circling Xena, and they both latitudes are concentric arcs of debris breaking away from steep look very similar to one another. This leads us to conclude that mountain alcoves -- just as they do at the heads of glaciers on the largest objects in the Kuiper belt may have been subject to Earth. As for how ice could reach Mars lower latitudes, orbital collisions." Van Dam described the discovery: "At first we saw calculations indicate that Mars may slowly wobble on its spin axis this little faint thing that kept cropping up in all the images, and we far more than Earth does (the Moon minimizes Earth's wobble). knew it was not a background star or galaxy because it moved This means that as Mars' axis tilted to the extremes -- up to 60 across the sky with the primary. We could also tell that it was not degrees from the plane of Mars' orbit -- the Martian poles get a an image artifact because it did not rotate with the sky and was whole lot more sunshine in the summertime than they do now. consistent in each of the 24 images. By morning we knew that we That extra sun would likely sublime water from the polar ice caps, had made a major discovery." The discovery of the moon's explains Head. "When you do that you are mobilizing a lot of ice primary, Xena, was announced July 29th by planetary and redistributing it to the equator," Head said. "The climate astronomers Mike Brown of Caltech, Chad Trujillo of Gemini models are saying it's possible." It's pure chance that we happen Observatory and David Rabinowitz of Yale University. It is to be exploring Mars when its axis is at a lesser, more Earth-like currently about 97 astronomical units from the Sun (an tilt. This has led to the false impression of Mars being a place astronomical unit is the 93-million-mile distance between the Sun that's geologically and climatically dead. In fact, says Head, Mars and Earth), and is larger than the size of Pluto. It takes 560 years is turning out to be a place that is constantly changing. to complete one trip around the Sun (versus 250 years for Pluto) and has a very steep angle in relation to the other planets, about TH MOON DISCOVERED ORBITING 10 PLANET 45 degrees off from the orbital plane of the other nine planets. Xena also has a very elliptical orbit, coming in as close as 3.5 New Class of Satellites Discovered - Scientists are over the moon billion miles (38 AU) and as far away as 9 billion miles. The at the Keck Observatory over a new discovery of a satellite names "Xena," "Gabrielle," "Santa" and "Easterbunny" are orbiting the Solar System's 10th planet (2003 UB313). The newly temporary nicknames until the International Astronomical Union discovered moon orbits the farthest object ever seen in the Solar (IAU) rules on their official names. The proposed names have System. The existence of the moon will help astronomers resolve been submitted to the IAU and will follow the mythological and the question of whether 2003 UB313, temporarily nicknamed spiritual traditions of Kuiper belt objects. Meanwhile, the IAU has "Xena," is more massive than Pluto and hence the 10th planet. stated it will not rule on a name until the IAU Working Group in "We were surprised because this is a completely different type of charge of defining a planet determines a minimum size for a satellite from anything we've seen before," said Dr. Mike Brown, planet. Until then, the IAU considers all objects discovered in the professor of Planetary Sciences. "It is essentially a new class of outer solar system as "Trans-Neptunian" objects. satellites to large Kuiper Belt objects. It is tiny compared to the primary, and much fainter. We have never seen satellites like this Adaptive Optics is a technique that corrects the effect of before." The newly discovered moon, which is 60 times fainter atmospheric blurring to produce images with a resolution than its parent body, is affectionately called "Gabrielle" after the comparable to what would be obtained from space. To measure faithful traveling companion to Xena on the syndicated TV series. atmospheric distortion, the adaptive optics system relies on a Future observations with the 10-meter Keck II telescope and the relatively bright guide star very close in the field of view to the will determine the moon's orbital scientific object of study. Since there was no naturally-occurring characteristics, which has an estimated period of about 14 days, guide star sufficiently bright enough with which to study Xena, and will therefore reveal the precise mass and density of Xena. astronomers used the Keck Laser Guide Star system to create an "What is interesting is that Xena, Pluto and Santa, three of the artificial star instead. four largest objects in the Kuiper belt, all have moons," said Dr. Marcos van Dam, adaptive optics scientist at the W. M. Keck METEORITES OFFER GLIMPSE OF THE EARLY EARTH Observatory and co-author on the paper describing the discovery. Important clues to the environment in which the early Earth "These moons suggest that these Kuiper belt objects may have formed may be emerging from scientists' recent study of a formed differently than smaller objects in the same region." particular class of meteorites. By examining the chemistry of 29 The moon circling Xena was first discovered with the Keck II chunks of rock that formed billions of years ago, probably in close telescope on September 10, 2005 (UT) using the Laser Guide proximity to our planet, two researchers, Michael E. Lipschutz and 7 Ming-Sheng Wang, have clarified our understanding of the agree on whether they originated from a single parent object or conditions present in the vicinity of the ancient Earth's orbit. two different ones. Unfortunately, Lipschutz said, the data from Because direct evidence for these conditions is lacking in the 29 ECs they analyzed were insufficient to settle the issue. terrestrial samples, the scientists believe that the composition of "There are still quite a few unanswered questions about the these so-called enstatite chondrite (EC) meteorites could offer a earliest periods of the Earth's history, and this study only provides window into the planet's distant past. "What happened to these one piece of the puzzle," he said. "But aspects of this study also rocks most likely happened to the Earth in its early stages - with show that ECs differ substantially from other meteorite types that one great exception," said Lipschutz. "Shortly after the early Earth came from much farther out in the disk, in the region of the formed, an object the size of Mars smashed into it, and the heat asteroid belt." For Lipschutz, who had an asteroid named for him from the cataclysm irrevocably altered the geochemical makeup on his 50th birthday in honor of his many studies of meteorites, of our entire planet. These EC meteorites, however, are likely their parent bodies and the early history of the solar system, formed of matter similar to that which formed the early Earth, but deeper answers may lie farther away than Antarctica. "If we they were not involved in this great collision and so were not understand how our solar system formed, we might be better able chemically altered. They might be the last remaining pristine bits to understand the processes at work in other solar systems, which of the material that became the planet beneath our feet." we are just beginning to discover," he said. "Probing the asteroid Lipschutz and Wang initially set out to increase our knowledge of belt could give us clues to these processes." EC meteorites, one of many different meteorite classes. Meteorites come from many different parts of the solar system, CASSINI'S DOUBLEHEADER FLYBYS SCORE HOME RUN and a scientist can link one with its parent object by determining the different isotopes of oxygen in a meteorite's minerals. Chunks Cassini performed back-to-back flybys of Saturn moons Tethys of the moon, the Earth and EC meteorites, for example, have very and Hyperion last weekend, coming closer than ever before to similar isotopic "signatures," quite different from those of Mars each of them. Tethys has a scarred, ancient surface, while and other objects formed in the asteroid belt. The variations Hyperion is a strange, spongy-looking body with dark-floored occurred because different materials condensed in different craters that speckle its surface. Images of Tethys taken during regions of the disk of gas and dust that formed the sun and Cassini's close approach to the moon on Sept. 24, 2005, reveal planets. Bits of these materials orbit the sun, occasionally falling an icy land of steep cliffs and craters. Cassini photographed the to earth as meteorites. But there is one place on our planet that moon's south pole, a region not seen by the Voyager spacecraft. meteorites accumulate and are preserved in a pristine fashion - the ice sheet of Antarctica. "Over the millennia, many thousands of meteorites have struck the Antarctic ice sheet, which both preserves them and slowly concentrates them near mountains sticking through the ice, much as ocean waves wash pebbles to the shore," said Lipschutz. "These stones have come from many different parts of the solar system and have given us a better picture of the overall properties of their parent objects." By examining their mineralogy, scientists have determined that about 200 of these Antarctic stones are EC meteorites that formed from the same local batch of material as the Earth did more than 4.5 ago. But there is additional information that the chemistry of these ECs can offer on the temperatures at which they formed. To obtain this information, however, required Lipschutz to analyze chemicals in the meteorites called volatiles - rare elements such as indium, thallium and cadmium. "Volatiles in meteorites can give unique information on their temperature histories, but only 14 of them had ever been analyzed for these elements," Lipschutz said. "Naturally, we want to know the story behind the formation of objects in our own neighborhood, so we set out to increase that number." In this study, the researchers gathered samples taken from another 15 EC meteorites that had, for the most part, landed in Antarctica tens of thousands of years ago. Using a unique method involving bombardment of the samples with neutrons, chemically separating the radioactive species and counting them, the researchers were able to A giant rift called Ithaca Chasma cuts across the disk of Tethys. determine the amounts of 15 volatiles that together offered clues Much of the topography in this region, including that of Ithaca to each rock's heating history. "Volatiles can act like Chasma, has been thoroughly hammered by impacts. This thermometers," Lipschutz said. "They can tell you whether the appearance suggests that the event that created Ithaca Chasma temperature was high or low when the rock formed. We tested happened very long ago. Near a prominent peaked crater named two different kinds of ECs, and the oldest, most primitive Telemachus are the remnants of a very old crater named examples of each kind had very similar volatile contents - which Teiresias. The ancient impact site is badly overprinted and eroded means their temperature at formation was similar. These rocks by impact weathering and degradation. All that remains is a have essentially recorded the temperature at which the early circular pattern of hummocks that mark where the old crater rim Earth formed, and we now know that this was much lower than existed. Many of the fresh-appearing craters exhibit unusually 500 degrees Celsius." The two different kinds of EC meteorites, bright crater floors, in contrast to the dark-floored craters seen on known as ELs and EHs, were found in the Purdue study to have Saturn's oddly tumbling moon Hyperion. condensed at low temperatures like the Earth. However, the two groups are controversial because scientists have not been able to 8 Images of Hyperion taken on Sept. 26 show a surface dotted with their colleagues at Caltech and the Gemini Observatory in Hawaii craters and modified by some process, not yet understood, to based their analysis on new images of distinctive clouds that create a strange, "spongy" appearance, unlike the surface of any sporadically appear in the middle latitudes of the moon's southern other Saturn moon. A false-color image of Hyperion reveals crisp hemisphere. The clouds provide the first explanation for a long- details and variations in color across the strange surface that standing Titan mystery: From where does the atmosphere's might represent differences in the composition of materials. copious methane gas keep coming? That methane is Hyperion has a notably reddish tint when viewed in natural color. continuously destroyed by the sun's ultraviolet rays, in a process called photolysis. This photolysis forms the thick blanket of haze enveloping the moon, and should have removed all of Titan's atmospheric methane billions of years ago. Clearly, something is replenishing the gas-and that something, say Roe and his colleagues, is geologic activity on the surface. "This is the first strong evidence for currently active methane release from the surface," Roe says. Adds Brown: "For a long time we've wondered why there is methane in the atmosphere of Titan at all, and the answer is that it spews out of the surface. And what is tremendously exciting is that we can see it, from Earth; we see these big clouds coming from above these methane vents, or methane volcanoes. Everyone had thought that must have been the answer, but until now, no one had found the spewing gun." Roe, Brown, and their colleagues made the discovery using images obtained during the past two years by adaptive optics systems on the 10-meter telescope at the W. M. Keck Observatory on Mauna Kea in Hawaii and the neighboring 8- meter telescope at the Gemini North Observatory. Adaptive optics is a technique that removes the blurring of atmospheric turbulence, creating images as sharp as would be obtained from space-based telescopes. "These results came about from a collaborative effort between two very large telescopes with adaptive optics capability, Gemini and Keck," says astronomer Chadwick A. Trujillo. "At both telescopes, the science data were collected from only about a half an hour of images taken over Scientists are extremely curious to learn what the dark material is many nights. Only this unusual 'quick look' scheduling could have that fills many craters on this moon. Features within the dark produced these unique results. At most telescopes, the whole terrain, including a 200-meter-wide (650-feet) impact crater night is given to a single observer, which could not have produced surrounded by rays and numerous bright-rimmed craters, indicate this science." that the dark material may be only tens of meters thick with The two telescopes observed Titan on 82 nights. On 15 nights, brighter material beneath. Scientists will also be examining the images revealed distinctive bright clouds-two dozen in all-at Cassini's sharp views in hopes of determining whether there have midlatitudes in the southern hemisphere. The clouds usually been multiple episodes of landslides on Hyperion. Such popped up quickly, and generally had disappeared by the next "downslope" movement is evident in the filling of craters with day. "We have several observations where on one night, we don't debris and the near elimination of many craters along the steeper see a cloud, the next night we do, and the following night it is slopes. Answers to these questions may help solve the mystery of gone," Roe says. Some of the clouds stretched as much as 2,000 why this object has evolved different surface forms from other km across the 5,150 km diameter moon. "An equivalent cloud on moons of Saturn. Cassini flew by Hyperion at a distance of only Earth would cover from the east coast to the west coast of the 500 kilometers (310 miles). Hyperion is 266 kilometers (165 United States," Roe says. Although the precise altitude of the miles) across, has an irregular shape, and spins in a chaotic clouds is not known, they fall somewhere between 10 km and 35 rotation. Much of its interior is empty space, explaining why km above the surface, within Titan's troposphere (most cloud scientists call Hyperion a rubble-pile moon. This flyby was activity on the earth is also within its troposphere). Cassini's only close encounter with Hyperion in the prime mission four-year tour. Over the next few months, scientists will study the Notably, all of the clouds were located within a relatively narrow data in more detail. Cassini flew by Tethys at a distance of band at around 40 degrees south latitude, and most were approximately 1,500 kilometers (930 miles) above the surface. clustered tightly near 350 degrees west longitude. Both their Tethys is 1,071 kilometers (665 miles) across and will be visited sporadic appearance and their specific geographic location led again by Cassini in the summer of 2007. the researchers to conclude that the clouds were not arising from the regular convective overturn of the atmosphere due to its CRACKS OR CRYOVOLCANOES? heating by the sun (which produces the cloud cover across the SURFACE GEOLOGY CREATES CLOUDS ON TITAN moon's southern pole) but, rather, that some process on the surface was creating the clouds. "If these clouds were due only to Like the little engine that could, geologic activity on the surface of the global wind pattern, what we call general circulation, there's Saturn's moon Titan-maybe outgassing cracks and perhaps icy no reason the clouds should be linked to a single longitude. cryovolcanoes-is belching puffs of methane gas into the They'd be found in a band around the entire moon," Roe says. atmosphere of the moon, creating clouds. This is the conclusion Another possible explanation for the clouds' patchy formation is of planetary astronomer Henry G. Roe, and Michael E. Brown, variation in the albedo, or brightness, of the surface. Darker professor of planetary astronomy at Caltech. Roe, Brown, and surfaces absorb more sunlight than lighter ones. The air above 9 those warmer spots would be heated, then rise and form gave them a 3-D view of the cloud and a six-frame movie that convective clouds, much like thunderstorms on a summer's day shows how it evolved over three hours. on Earth. Roe and his colleagues, however, found no differences in the brightness of the surface at 40 degrees south latitude. "The structure of the clouds turns out to be complicated," Griffith Clouds can also form over mountains when prevailing winds force said. "We detected not one region, but many regions of cloud air upward, but in that case the clouds should always appear in formation. Each long cloud consists of a number of vigorous the identical locations. "We see the clouds regularly appear in the storms where clouds rise to 40 kilometers altitude (25 miles) in a couple of hours and dissipate in the next half hour. The rate of same geographic region, but not always in the exact same cloud ascent and dissipation suggests that we are witnessing the location," says Roe. formation of convective clouds, likely similar to thunderstorms, The other way to make a cloud on Titan is to raise the humidity by that disappear through rainfall. “ directly injecting methane into the atmosphere, and that, the "Over the next several hours we see the clouds form long tails, scientists say, is the most likely explanation here. Exactly how the indicating that strong westerly winds stretch out the clouds and methane is being injected is still unknown. It may seep out of carry the particles downwind a thousand kilometers (more than transient cracks on the surface, or bubble out during the eruption 600 miles). This detailed look into the structure of these clouds of icy cryovolcanoes. Although no such features have yet been reveals that the clouds evolve from a number of small active cloud observed on the moon, Roe and his colleagues believe they may formation centers lined up like an uneven string of beads long 40 be common. "We think there are numerous sources all over the degrees south latitude. These localized storms cause a healthy surface, of varying size, but most below the size that we could rain, and very long clouds, once the wind has stretched them out." see with our instruments," he says. One large feature near 350 degrees west longitude is probably creating the clump of clouds Griffith argues that it's improbable that many ice volcanoes, all that forms in that region, while also humidifying the band at 40 aligned at 40 degrees south latitude, are forming these clouds. In degrees latitude, Roe says, "so you end up creating areas where addition, the scientists estimate that the cloud activity at zero the humidity is elevated by injected methane, making it easier for degrees longitude, if volcanic, does not appear to spew out another, smaller source to also generate clouds. They are like enough methane to create the mid-latitude cloud band. Smaller weather fronts that move through. So we are seeing weather, on clouds actually lie upwind of the main cloud at zero degrees another planet, with something other than water. With methane. longitude, they note. The team also conclude that the clouds That's cool. It's better than science fiction." aren't obviously caused by Saturn's tidal pull on Titan's atmosphere. They also don't find evidence that mountains and STORMY WEATHER: TITAN’S ENIGMATIC CLOUD BAND IS lakes might cause mountain clouds or marine clouds, Griffith said. CONVECTIVE "We believe that it's no coincidence that Titan's south polar cap of Scientists say that the peculiar clouds at middle latitudes in smog extends from the pole to 40 degrees south latitude -- Titan's southern hemisphere may form in the same way as exactly where the methane cloud band appears," Griffith said. distinct bands of clouds form at Earth's equator. "Titan's weather The researchers suggest that global circulation may cause the air is very different from Earth's," said Caitlin Griffith. "If you walked to rise at this attitude on Titan, much as clouds form in a band past Titan's minus-40-degree-latitude line, you might be showered around the Earth's equator and rain on the Caribbean islands. with liquid natural gas. If you decided to visit Titan's south pole, "Such rising air would cut off air from the south polar region from you might encounter a storm the size of a hurricane which also mixing with the rest of the moon's atmosphere, causing smog to consists of methane, more commonly known as natural gas," build up and form a cap over the pole," Griffith added. Griffith said. "Otherwise, don't expect clouds on Titan." Theoretical modeling supports the team's conclusion, Griffith said. Titan's weather forecast has remained the same for years, and Pascal Ranou and his group in Paris studied Titan's circulation that baffles scientists. They don't understand why clouds a with an elaborate and complicated general circulation model. His thousand miles long stretch over the temperate latitude. "Imagine model predicts that solar heating naturally creates rising air on how curious it would be if beyond Earth's poles, clouds existed Titan at 40 degrees south latitude. The next mystery is why only at the latitude that crosses New Zealand, Argentina and Titan's southern mid-latitude clouds are bunched at zero degrees Chile," Griffith said. "Furthermore, Henry Roe and his colleagues longitude. There's no evidence yet that volcanoes, mountain find that most of these peculiar clouds bunch up at zero degrees ranges or Saturn's tides are involved, Griffith said. "What's and 90 degrees longitude, analogous to Earth longitudes causing the bunching is unclear, and likely involves unknown southwest and southeast of the Cape of Good Hope," she added. features on Titan's still largely unexplored surface," Griffith said. The highly localized nature of the clouds suggests that they have something to do with Titan's surface, Griffith said. Scientists think NEW ANALYSIS PUTS DARK MATTER BACK INTO ELLIPTICAL ice volcanoes must be venting methane -- the gas that condenses GALAXIES as clouds -- into Titan's hazy, mostly nitrogen atmosphere. According to the prevailing "cold dark matter" theory of the Otherwise, the moon's atmospheric methane would have evolution of the universe, every galaxy is surrounded by a halo of vanished billions of years ago because methane is destroyed by dark matter that can only be detected indirectly by observing its ultraviolet sunlight. gravitational effects. This theory faced a challenge in 2003, when Griffith, Paulo Penteado and Robert Kursinski studied the origin of a team of astronomers reported a surprising absence of dark the clouds by analyzing cloud height and thickness using images matter in elliptical galaxies. But a new analysis published in the from Cassini's visual and infrared mapping spectrometer (VIMS). Sep 29 issue of the journal Nature provides an explanation for the This instrument is among a suite of instruments on the Cassini earlier observations that fits comfortably with the standard theory spacecraft orbiting Saturn. It measures light at 256 different and puts the dark matter back into elliptical galaxies. wavelengths. Griffith is a member of the VIMS team, headed by "These are very normal, nearby elliptical galaxies that they Robert Brown. Griffith and her colleagues analyzed images that studied, and if those galaxies don't have dark matter it calls into question the whole theory of cold dark matter," said Joel Primack, 10 a coauthor. "A dearth of dark matter in elliptical galaxies is great distances, so the two galaxies essentially pass through one especially puzzling in the context of the standard theory of galaxy another. But the huge gravitational fields of the galaxies cause formation, which assumes that ellipticals originate from mergers powerful tidal disturbances. Some of the stars are flung outward in of disk galaxies," added Avishai Dekel. "Massive dark matter extended tidal tails as the cores of the galaxies pass close by one halos are clearly detected in disk galaxies, so where did they another and spin apart. Sometimes the cores remain connected disappear to during the mergers?" said Dekel. Primack, one of the by a tidal bridge of stars and gas. Eventually, gravity pulls the originators and developers of the cold dark matter theory, uses cores back together, and the stars that were flung outward fall supercomputers to run simulations of galaxy formation and the back in toward the center. "In the merger process that produces evolution of structure in the universe. The new paper used these galaxies, a lot of the stars get flung out to fairly large simulations of galaxy mergers run last year by Thomas J. Cox, distances, and they end up in highly elongated orbits that take then a graduate student working with Primack at UCSC and now them far away and then back in close to the center," Primack a postdoctoral researcher at Harvard University. said. The simulations show that the observations reported in 2003 are To an observer outside the galaxy, a star on such an elongated a predictable consequence of the violent galactic mergers that orbit would only appear to be far from the if the give rise to elliptical galaxies, Primack said. The simulations were long axis of its orbit is more or less perpendicular to the analyzed by Dekel, Felix Stoehr, and Gary Mamon. Graduate observer's line of sight. If the long axis of the orbit is aligned with student Greg Novak also contributed to the analysis. the line of sight, the star would always appear to be in the crowded center of the galaxy from the perspective of the Elliptical galaxies are thought to form when two spiral galaxies observer. "If we see a star at a large distance from the center of collide and merge. Whereas spiral galaxies are dominated by the galaxy, that star is going to be mostly moving either away flattened, rotating disks of stars and gas, elliptical galaxies are from the center or back toward the center. Almost certainly, most round, smooth collections of stars. Evidence for dark matter halos of its motion is perpendicular to our line of sight," Primack said. around spiral galaxies comes from studying the circular motions The simulated mergers involved typical spiral galaxies, each of stars in these galaxies. Because most of the visible mass in a embedded in a halo of cold dark matter. The simulations followed galaxy is concentrated in the central region, stars at great the gravitational and hydrodynamic evolution of the merger distances from the center would be expected to move more slowly systems, taking into account the complicated feedbacks from star than stars closer in. Instead, careful observations of spiral formation, supernovae, and the heating and cooling of gases in galaxies show that the rotational speed of stars in the outskirts of the galaxies. Each simulation was then "observed" from three the disk remains constant as far out as astronomers can measure different directions and at two slightly different times after the it. The reason for this, according to cold dark matter theory, is the merger. From more than 200 merger simulations run by Cox on a presence of an enormous halo of unseen dark matter surrounding supercomputer at UCSC, the researchers analyzed 10 mergers the galaxy and exerting its gravitational influence on the stars. that yielded elliptical galaxies with masses similar to those of the Additional support for dark matter halos has come from a variety galaxies observed in 2003. The results were completely of other observations. In elliptical galaxies, however, it has been consistent with the reported observations, Primack said. "Our difficult to study the motions of stars at great distances from the conclusion is that what they saw is exactly what the cold dark center. The 2003 study (A. J. Romanowsky et al., Science matter model would predict," he said. "Their data are great, and 301:1696-1698) focused on bright planetary in the outer this actually gives us more insight into how elliptical galaxies parts of four nearby elliptical galaxies. Planetary nebulas are old form." "We predict that other velocity tracers in the same elliptical stars that have blown off their outer layers and glow brightly in galaxies will show higher velocities if they are less concentrated characteristic wavelengths of light. The researchers were able to toward the galaxy center or if they move on more circular orbits," determine the line-of-sight velocities of large numbers of planetary Dekel said. "This is likely to be the case for compact star clusters, nebulas in these elliptical galaxies. They found a decrease in the which are also observable in the outskirts of elliptical galaxies." velocities with increasing distance from the center of the galaxy, which is inconsistent with simple models of the gravitational effects of dark matter halos. THIS JUST WON'T FADE AWAY Scientists say that a star which exploded in 1979 still shines as Part of the explanation put forth in the new Nature paper lies in brightly in X-rays today as it did when X-ray telescopes first the fact that the velocities were measured along the line of sight. observed it years ago. This is a surprise finding because such "You cannot measure the absolute speeds of the stars, but you objects usually fade significantly after only a few months. can measure their relative speeds along the line of sight, because if a star is moving toward us its light is shifted to shorter The scientists could document a unique history of the star, both wavelengths, and if it is moving away from us its light is shifted to before and after the explosion, by studying rings of light leftover longer wavelengths," Primack explained. This limitation would not from the blast, similar to the way climate history is derived from be a problem if the orbits of the observed stars were randomly analyzing rings in a tree trunk. Dr. Stefan Immler, led this oriented with respect to the line of sight, because any differences observation using the European Space Agency's XMM-Newton resulting from the orientations of the orbits would average out observatory. The star explosion (supernova), called SN 1979C, over a large number of observations. According to Cox's shows no sign of letting up, he said. "This 25-year-old candle in simulations, however, the stars farthest from the center of the the night has allowed us to study aspects of a star explosion galaxy at any given time are likely to be moving in elongated, never before seen in such detail," Immler said. "All the important eccentric orbits such that most of their motion is perpendicular to information that usually fades away in a couple of months is still the line of sight. Therefore, they could be moving at high there." Among the many unique finds, Immler said, is the history velocities without exhibiting much motion toward or away from the of the star's stellar wind dating back 16,000 years before the observers. explosion. Such a history is not even known about our Sun. Also, the scientists could measure the density of the material around To understand why, it is necessary to look at what happens to the the star, another first. The lingering mystery, though, is how this stars during galaxy mergers. As the merging galaxies interact, the stars themselves do not collide because they are separated by 11 star could fade away in visible light yet remain so radiant in X- scientists discovered longer bursts, lasting more than two rays. seconds, arise from the explosion of very massive stars. About 30 percent of bursts are short and under two seconds. Stars explode when they run out of fuel to burn. Stars more than 10 times the mass of our Sun will explode in an event called a The Swift satellite detected a short burst on May 9, and the High- core-collapse supernova. Without fuel and thus energy to support Energy Transient Explorer (HETE) detected another on July 9. its gravity, such stars first implode. The core reaches a critical The May 9 event marked the first time scientists identified an density, and much of the infalling matter gets bounced back out afterglow for a short gamma-ray burst, something commonly seen violently into space by powerful shockwaves. Supernovae can after long bursts. "We had a hunch that short gamma-ray bursts outshine an entire galaxy and are often easily seen in neighboring came from a neutron star crashing into a black hole or another galaxies with a backyard telescope. Supernovae are typically half neutron star, but these new detections leave no doubt," said Dr. as bright after about ten days and fade steadily after that, Derek Fox. Fox is lead author of one report detailing a multi- regardless of the wavelength. SN 1979C has in fact faded in wavelength observation. Fox's team discovered the X-ray optical light which is now just barely visible with a good amateur afterglow of the July 9 burst with the Chandra X-ray Observatory. telescope. In X-rays, however, this supernova is still the brightest A team led by Jens Hjorth, identified the optical afterglow using object in its host galaxy. "We can use the X-ray light from SN the Danish 1.5-meter telescope at the La Silla Observatory in 1979C as a 'time machine' to study the life of a dead star long Chile. Fox's team continued studying the afterglow with Hubble before it exploded," Immler said. Immler's team will attempt to Space Telescope and ground-based telescopes, and the National identify the history of the star that created SN 1979C through a Radio Astronomy Observatory. process similar to counting rings in a tree trunk. This star, about 18 times more massive than our Sun, produced fierce stellar "The July 9 burst was like the dog that didn't bark," said Dr. winds. That material was flung into space for millions of years, George Ricker, HETE principal investigator. "Powerful telescopes creating concentric rings around the star and the X-rays have detected no supernova as the gamma-ray burst faded, arguing illuminated 16,000 years' worth of stellar activity. Immler against the explosion of a massive star. Also, the July 9 burst, and probably the May 9 burst, are located in the outskirts of their speculates that the abundance of stellar wind has provided ample host galaxies, just where old merging binaries are expected," he material to keep SN 1979C glowing so brightly. "XMM-Newton is added. Mergers create gravitational waves, ripples in space-time known among scientists as a superior X-ray observatory, but the predicted by Einstein but never directly detected. The July 9 burst study of SN 1979C demonstrates the importance of the satellite's simultaneously observing UV and optical telescope," said Dr. was about 2 billion light-years away. A big merger closer to the Norbert Schartel, XMM-Newton Project Scientist. Earth could be detected by the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO). If Swift detects a nearby short burst, scientists could go back and FLASH HELPS SOLVE 35-YEAR-OLD COSMIC MYSTERY check the data with a precise time and location. "This is good Scientists have solved the 35-year-old mystery of the origin of news for LIGO," said Dr. Albert Lazzarini. "The connection powerful, split-second flashes of light known as short gamma-ray between short bursts and mergers firms up projected rates for bursts. These flashes, brighter than a billion suns, yet lasting only LIGO, and they appear to be at the high end of previous a few milliseconds, have been simply too fast to catch -- until now. estimates. Also, observations provide tantalizing hints of black Through the unprecedented coordination of observations from hole-neutron star mergers, which have not been detected before," several ground-based telescopes and NASA satellites, scientists he said. determined the flashes arise from violent collisions in space. The clashes are either between a black hole and a neutron star or FROM THE EDITOR'S TERMINAL between two neutron stars. In either scenario, the impact creates The Stargazer is your newsletter and therefore it should be a a new black hole. In at least one burst, scientists saw tantalizing, cooperative project. Ads, announcements, suggestions, and literary first-time evidence of a black hole eating a neutron star. The works should be received by the editor before the 1st of the month of neutron star was first stretched into a crescent, then swallowed by publication, for example, material for May's newsletter should be the black hole. These observations could enable direct detection received May 1st. If you wish to contribute an article or suggestions to of exotic gravitational waves that have never before been seen. The Stargazer please contact Mark Folkerts by email or by telephone "Gamma-ray bursts in general are notoriously difficult to study, but the shortest ones have been next to impossible to pin down," said (425) 486-9733 or co-editor Bill O’Neil, at (774) 253-0747. Dr. Neil Gehrels, principal investigator for the Swift satellite. "All that has changed. We now have the tools in place to study these events," he said. Gamma-ray bursts, first detected in the 1960s, are the most powerful explosions known. They are random, fleeting and can occur from any region of the sky. Two years ago, 12 The Star Gazer P.O. Box 12746 Everett, WA 98206

In October’s Stargazer:

**** OBSERVER'S INFORMATION **** ASTRO CALENDAR **** CONSTELLATIONS OF THE MONTH: **** ASTRONOMY FUN FACTS **** YOUNG ASTRONOMER’S CORNER **** ASTRONOMY AND TELESCOPE LINGO **** NEW MAP PROVIDES MORE EVIDENCE MARS ONCE LIKE EARTH **** CASSINI'S DOUBLEHEADER FLYBYS SCORE HOME RUN **** CRACKS OR CRYOVOLCANOES? SURFACE GEOLOGY CREATES CLOUDS ON TITAN **** STORMY WEATHER: TITAN’S ENIGMATIC CLOUD BAND IS CONVECTIVE **** NEW ANALYSIS PUTS DARK MATTER BACK INTO ELLIPTICAL GALAXIES

**** THIS SUPERNOVA JUST WON'T FADE AWAY

**** FLASH HELPS SOLVE 35-YEAR-OLD COSMIC MYSTERY **** MARS LOOMS BIG AND BRIGHT AS IT SWINGS CLOSE TO EARTH

The next EAS Meeting is 3:00 P.M. SATURDAY, October 29th at the Everett Public Library Auditorium.